Paper feeding device and paper skew judging module applied therein

Abstract

A paper feeding device includes a lower cover, an upper cover pivotally connected to the lower cover, at least one motor mounted to the lower cover, a feeding roller assembly and a paper skew judging module. The feeding roller assembly is pivotally connected to the lower cover and connected with the at least one motor. The paper skew judging module disposed to the lower cover, has an infrared light emitter, an infrared light receiver, a cantilever arm rotatably assembled to the lower cover, a sensing roller pivotally connected with the cantilever arm, and a lens. The infrared light emitter is mounted to the lower cover. The infrared light receiver is mounted to the lower cover and is disposed opposite to the infrared light emitter. The lens is fastened to the cantilever arm, and disposed between the infrared light emitter and the infrared light receiver. The lens has different photopermeabilities.

What is claimed is: 
     
       1. A paper feeding device for feeding paper, comprising:
 a lower cover; 
 an upper cover pivotally connected to the lower cover, a paper feeding channel being formed between the upper cover and the lower cover; 
 at least one motor mounted to the lower cover; 
 a feeding roller assembly pivotally connected to the lower cover and projecting into the paper feeding channel, the feeding roller assembly being connected with the at least one motor, the at least one motor driving the feeding roller assembly to feed the paper into the paper feeding device along a paper feeding direction; and 
 a paper skew judging module disposed to the lower cover for judging whether the fed paper is skewed or not, the paper skew judging module having an infrared light emitter, an infrared light receiver, a cantilever arm, a sensing roller and a lens, the infrared light emitter being mounted to the lower cover, the infrared light receiver being mounted to the lower cover and being disposed opposite to the infrared light emitter for receiving infrared light emitted from the infrared light emitter, the cantilever arm being rotatably assembled to the lower cover, the sensing roller being pivotally connected with a top end of the cantilever arm, a center axis of the sensing roller extending along a direction perpendicular to the paper feeding direction, a top of the sensing roller projecting into the paper feeding channel, the lens being fastened to the cantilever arm, and disposed between the infrared light emitter and the infrared light receiver, different areas of the lens having different photopermeabilities, the infrared light receiver being used for receiving infrared light emitted from the infrared light emitter and penetrating through the lens. 
 
     
     
       2. The paper feeding device as claimed in  claim 1 , wherein the lower cover includes a base holder, a sealing board and a base board, a middle of a top surface of the base holder is concaved downward to form a receiving space, the sealing board is covered to the top surface of the base holder, the paper feeding channel is formed between a top surface of the sealing board and a bottom surface of the upper cover, the sealing board forms two first openings arranged transversely and spaced from each other, the two first openings are located above the receiving space and communicated between the receiving space and the paper feeding channel, the feeding roller assembly includes two feeding rollers arranged transversely and spaced from each other, the two feeding rollers are pivotally connected to the base holder and are received in the receiving space, the two feeding rollers project beyond the top surface of the sealing board through the two first openings, a center axis of the two feeding rollers extends along the direction perpendicular to the paper feeding direction, the base board is disposed under the base holder, the infrared light emitter and the infrared light receiver are both fastened on the base board. 
     
     
       3. The paper feeding device as claimed in  claim 2 , wherein the sealing board forms a second opening located between the two first openings, the sensing roller projects beyond the top surface of the sealing board through the second opening and projects into the paper feeding channel, a top of the sensing roller projects beyond the two feeding rollers, a center axis of the sensing roller and the center axis of the two feeding rollers are arranged in sequence, the center axis of the sensing roller is located between the center axis of the two feeding rollers and an initiating end of the paper feeding channel. 
     
     
       4. The paper feeding device as claimed in  claim 2 , wherein the cantilever arm includes a first supporting arm, a second supporting arm and a spring, the first supporting arm is pivotally connected to the base holder along the direction perpendicular to the paper feeding direction, the first supporting arm is received in the receiving space, the second supporting arm is pivotally connected to a top of the first supporting arm and is capable of rotating upward and downward with respect to the paper feeding direction, one end of the spring is fastened to a rear surface of the first supporting arm, and the other end of the spring is fastened to a bottom end of the second supporting arm, so that the second supporting arm keeps a status of inclining upward and having an elasticity with respect to the first supporting arm, the sensing roller is pivotally connected with a tail end of the second supporting arm. 
     
     
       5. The paper feeding device as claimed in  claim 4 , wherein a bottom of the base holder opens a pivoting hole communicated with the receiving space, a bottom surface of the first supporting arm protrudes downward to form a fastening pillar, the bottom surface of the first supporting arm abuts against a bottom wall of the receiving space, the fastening pillar is received in the pivoting hole and projects beyond a bottom surface of the base holder, the lens has a connecting portion extending in the paper feeding direction and located above the base board, and a main portion fastened to one end of the connecting portion, the main portion is disposed on the base board and disposed between the infrared light emitter and the infrared light receiver, the other end of the connecting portion is defined as a fastening end, the fastening end of the connecting portion is fastened to a bottom of the fastening pillar. 
     
     
       6. The paper feeding device as claimed in  claim 5 , wherein a surface of the main portion of the lens facing to the infrared light emitter is an arc-shaped surface arched inward away from the infrared light emitter. 
     
     
       7. The paper feeding device as claimed in  claim 5 , wherein thicknesses of two opposite sides of the main portion of the lens are different, the two opposite sides of the main portion of the lens with the different thicknesses are a left side and a right side, the left side and the right side of the main portion are arranged opposite to each other along the direction perpendicular to the paper feeding direction, and the left side and the right side of the main portion are perpendicular to the base board, a gradual transition is formed from the thickness of one side of the main portion to the thickness of the other side of the main portion. 
     
     
       8. The paper feeding device as claimed in  claim 5 , wherein an inside of the main portion is added with a light blocking agent. 
     
     
       9. The paper feeding device as claimed in  claim 5 , wherein an outer surface of the main portion is coated with a light blocking agent. 
     
     
       10. The paper feeding device as claimed in  claim 9 , wherein the light blocking agent is titanium dioxide. 
     
     
       11. The paper feeding device as claimed in  claim 5 , wherein each of different areas of an outer surface of the main portion has one of different textures, indentations, shapes and other designs. 
     
     
       12. The paper feeding device as claimed in  claim 1 , wherein an outside of the sensing roller is sleeved with a rubber ring.